The systematics of the pelagic squid genus Octopoteuthis Ruppell, 1844 (Cephalopoda: Teuthoidea) with emphasis on species in the north Atlantic

Stephen, Stephen J. (1985) The systematics of the pelagic squid genus Octopoteuthis Ruppell, 1844 (Cephalopoda: Teuthoidea) with emphasis on species in the north Atlantic. Masters thesis, Memorial University of Newfoundland.

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Abstract

The systematics of the pelagic squid genus Octopoteuthis Ruppell, 1844 is reviewed. Four hundred and fifty-six specimens were examined from museum sources worldwide ranging in size from 1.3 mm - 240 mm dorsal mantle length (ML). Of the nine nominal species five are found to be invalid or considered nomina dubia. All species are found to bear photophores in a variety of body locations. Characters used to separate species include presence of one or two photophores on the posterior-ventral portion of the mantle; presence or absence of anterior eyelid photophores; presence or absence of an eyeball photophore; and presence or absence of accessory cusps (booklets) on the arm hooks. Larval specimens (those less than approximately 25 mm ML and still bearing tentacles or remnants of them) could not be separated into species at present because of the late development of the characters defined above. Discriminant analysis run on morphometric data on each specimen supported the species separation proposed here. Geographic and vertical distribution is also discussed.

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